Zinc fingers are a class of DNA binding proteins that can be designed to recognize DNA sequences according to a recently devised recognition code. This development has opened up the possibility of designing chimeric transcription respressors, transactivators and endonucleases for regulating or inactivating specific viral and human genes. we propose to utilize this emerging technology to develop drugs capable of inhibiting expression of an essential HIV gene. In Phase I, we constructed and characterized the binding affinities for three designer zinc finger proteins that target adjacent conserved, 9 base-pair sequences in an essential HIV gen. In Phase II, we will determine the ability of these proteins to bind HIV DNA sequences and attenuate growth of HIV in vivo. We will also link pairs of the zinc finger proteins with a peptide linker to construct hybrid DNA binding proteins with up to 18 base-pair specificity. This research will lead to the development of therapeutic drugs for attenuating viral reproduction. More generally, the development of designer DNA binding protein technology will lead to the development of novel therapeutics for treating a variety of viral and human diseases, including cancer, infectious diseases and autoimmune disorders. PROPOSED COMMERCIAL APPLICATION: The designer DNA binding proteins that we propose to develop will be an important proof-of-principle for a new class of anti-viral drugs. Their most immediate potential application is in the detection of viral DNA sequences for diagnostic proposes. the longer term potential therapeutic applications are to selectively inhibit viral gene expression within infected cells to help in reducing viral load.